I think they have to go through another round of voting in Puerto Rico. The vote was convoluted:

The two-part referendum asked whether the island wanted to change its 114-year relationship with the United States. Nearly 54 percent, or 922,374 people, sought to change it, while 46 percent, or 786,749 people, favored the status quo. Ninety-six percent of 1,643 precincts were reporting as of early Wednesday.

The second question asked voters to choose from three options, with statehood by far the favorite, garnering 61 percent. Sovereign free association, which would have allowed for more autonomy, received 33 percent, while independence got 5 percent.

So to me that means 61% of the people who voted to change it (54% overall) wanted to join the US.

Congress ultimately has to approve any change in status for the island and U.S. political leaders have long said that a prerequisite would include clear demonstration of popular support for a particular status.

Resident Commissioner Pedro Pierluisi, a member of the pro-statehood party and a Democrat who serves as the island's non-voting member of Congress won reelection with just over 48 percent of the vote. He said that he would present the results of the referendum to the Obama administration with the hopes of moving forward on statehood.

"The ball is now in Congress' court and Congress will have to react to this result," Pierluisi said, according to the Associated Press. "This is a clear result that says 'no' to the current status."